库布齐沙漠不同林龄沙柳林对土壤酶活性的影响

Effects of Different Ages of Salix Psammophila Forest on Soil Enzyme Activity in Hobq Desert

[目的]揭示库布齐沙漠灌木林营造对沙区土壤作用的生物机制,为建立合理有效的沙漠防护林体系提供理论支撑。[方法]以不同林龄(6,12和15 a)沙柳为研究对象,于2023年7月初采集库布齐沙漠沙柳林下0—10,10—20,20—30 cm土层深度土壤,对土壤主要理化性质及酶活性进行分析,分析该区植被恢复对土壤的作用机制。[结果](1)随着林龄的增加,与对照相比,细颗粒含量逐渐增多,土壤容重和pH值呈降低趋势。(2)土壤养分和酶活性在垂直方向上呈现较明显的表聚现象;土壤养分和酶活性在不同沙柳林龄下差异显著(p<0.05),12 a沙柳林下土壤碱解氮、速效磷、速效钾、碱性磷酸酶、过氧化氢酶分别为裸沙的316.4%,420.3%,134.6%,164.5%和94.8%,15 a沙柳林下的有机碳、脲酶、蔗糖酶较对照增长了186.2%,145.3%,2703.4%。(3)土壤酶活性与不同林龄恢复阶段土壤碱解氮、速效磷、速效钾、有机碳密切相关。[结论]库布齐沙漠沙柳防护林营建后,对土壤养分和酶活性具有显著的改良作用。

[Objective] The biological mechanisms underlying the effect of shrub forest development on soil in the Hobq Desert was analyzed in order to provide theoretical support for the establishment of a reasonable and effective desert shelter forest system.[Methods] Soil from 0—10,10—20 cm,and 20—30 cm soil layers in a Salix psammophila forest system with different forest ages(6,12,and 15 years) in the Hobq Desert was collected in early July 2023.The main physical and chemical properties and enzyme activities of the soil were analysed to reveal the mechanism of vegetation restoration on soil in this area.[Results](1) The fine particle content increased gradually with increasing forest age,whereas the soil bulk density and pH value decreased.(2) Soil nutrients and enzyme activity levels clearly indicated surface aggregation in the vertical direction.There were significant differences in soil nutrients and enzyme activity levels among the different S.psammophila forest ages(p<0.05).The soil alkali-hydrolysable nitrogen,available phosphorus,available potassium,alkaline phosphatase activity,and catalase activity in the 12-year S.psammophila forest were 316.4%,420.3%,134.6%,164.5%,and 94.8% higher than those of bare sand,respectively.Organic carbon,urease activity,and invertase activity under 15-year S.psammophila were 186.2%,145.3%,and 2 703.4% higher than those of CK,respectively.(3) Soil enzyme activity was closely related to soil alkali-hydrolysable nitrogen,available phosphorus,available potassium,and organic carbon in different forest age restoration stages.[Conclusion] The establishment of the S.psammophila shelter forest in the Hobq Desert significantly improved soil nutrient levels and enzyme activity.